Same issue for me as well, however I haven't found (haven't searched for) the culprit block. I have a line on x coords which when I pass, it gives a huge lag spike.
1.6.4
edit: I've found the source for me, I hope it helps for some of you: I have the "More Mob Heads" Vanilla Tweaks datapack added. Over the years I moved the map to a server, then to single player, then back to server, long story short, some mob heads are not displayed and I cannot fix it. I narrowed the lag source to one chunk, then I found that it was a tabby cat head, which wasn't displayed properly (Steve head instead)
Attila Nagy
Same issue for me as well, however I haven't found (haven't searched for) the culprit block. I have a line on x coords which when I pass, it gives a huge lag spike.
1.6.4
edit: I've found the source for me, I hope it helps for some of you:
I have the "More Mob Heads" Vanilla Tweaks datapack added. Over the years I moved the map to a server, then to single player, then back to server, long story short, some mob heads are not displayed and I cannot fix it. I narrowed the lag source to one chunk, then I found that it was a tabby cat head, which wasn't displayed properly (Steve head instead)